Is kissing other people bad if it doesn't mean anything

Started dating my girlfriend not long and had a discussion earlier that turned into an argument..she said she feels trapped in a relationship and asked if she could kiss people at parties if she's dared and if it doesn't mean anything and how she doesn't find it bad and she's spontaneous and I don't agree she should kiss other people and now it's kind of on a verge of a break up but we don't want to? Any ideas on what to do?